1. Field of the Invention
The invention is related to the field of magnetic recording disk drive systems and, in particular, to fabricating a magnetic read heads with a reduced scratch exposure region.
2. Statement of the Problem
Magnetic hard disk drive systems typically include a magnetic disk, a recording head having write and read elements, a suspension arm, and an actuator arm. As the magnetic disk is rotated, air adjacent to the disk surface moves with the disk. This allows the recording head (also referred to as a slider) to fly on an extremely thin cushion of air, generally referred to as an air bearing. When the recording head flies on the air bearing, the actuator arm swings the suspension arm to place the recording head over selected circular tracks on the rotating magnetic disk where signal fields are written to and read by the write and read elements, respectively. The write and read elements are connected to processing circuitry that operates according to a computer program to implement write and read functions.
In a disk drive, particles are often generated within the disk enclosure. Occasionally, these particles are drawn between the magnetic disk and an air bearing surface of the read head. As these particles are squeezed between the read head and the magnetic disk, a small amount of mechanical deformation may occur on the read head. Typically, this mechanical deformation occurs across elements of the read head that are not significantly affected by the deformation. Thus, the mechanical deformation does not affect subsequent performance of the read head. However, if the deformation is across the read gap of the read head where two leads (e.g., two shields) are separated by a very thin insulating gap, then metallic material can be smeared across the read gap. The likelihood of smearing depends on the size of the gap between the two shields. The size of the gap between the shields is often reduced by the addition of hard bias magnets between the shields on either side of the read element. Smears of metallic material between the two shields may permanently degrade the performance of the read head. The area of a read head that is susceptible to smearing between the shields is referred to as the scratch exposure region.
It is therefore desirable to reduce the scratch exposure region so that shorting of the leads is less likely. One way of decreasing the scratch exposure region is to minimize the track width of the read element and to minimize the size of the hard bias magnets on either side of the read element. Unfortunately, there are limitations in present lithographic fabrication processes, such as mask alignment and sizing issues, which restrict decreasing the size of these components during their formation. Thus, it is a problem for manufacturers of read heads to adequately decrease the size of the scratch exposure region of the read heads.